A dual-regulation strategy of B/N codoped CNT-encapsulated Ni nanoparticles as a catalytic host and separator coating promises high-performance Li-S batteries

A dual-regulation strategy of adopting B/N codoped carbon nanotube-encapsulated nickel nanoparticles(Ni@BNCNT) as a sulfur host and separator coating is proposed for high-performance Li-S batteries. On the cathode side, the 3D conductive network structure of Ni@BNCNT is favorable for high sulfur utilization, and the collaboration between polar metal Ni nanoparticles(NPs) and doped B/N elements facilitates the chemical adsorption of Li polysulfides(Li PSs). In addition, these metal Ni NPs exhibit a satisfactory catalytic effect on the polysulfide conversion. Moreover, using the Ni@BNCNT interlayer can further capture the soluble Li PSs, make them convert quickly, and prevent them from diffusing toward the anode side. The Li-S batteries simultaneously equipped with a S/Ni@BNCNT cathode and Ni@BNCNT interlayer show high reversible capacity and good cycle stability. Additionally, even at a sulfur loading of 3.5 mg cm;and an electrolyte/sulfur ratio of 3 μL mg;, excellent battery performance can be achieved. We believe that this work offers a new strategy based on combining a catalytic host and separator coating to construct high-efficiency Li-S batteries.

Improving sulfur transformation of lean electrolyte lithium-sulfur battery using nickel nanoparticles encapsulated in N-doped carbon nanotubes

Efficient redox reactions of lean electrolyte lithium-sulfur(Li-S)batteries highly rely on rational catalyst design.Herein,we report an electrocatalyst based on N-doped carbon nanotubes(CNT)-encapsulated Ni nanoparticles(Ni@NCNT)as kinetics regulators for Li-S batteries to propel the polysulfide-involving multiphase transformation.Moreover,such a CNT-encapsulation strategy greatly prevents the aggregation of Ni nanoparticles and enables the extraordinary structural stability of the hybrid electrocatalyst,which guarantees its persistent catalytic activity on sulfur redox reactions.When used as a modified layer on a commercial separator,the Ni@NCNT interlayer contributes to stabilizing S cathode and Li anode by significantly retarding the shuttle effect.The corresponding batteries with a 3.5 mg cm^(−2)sulfur loading achieve the promising cycle stability with~85%capacity retention at the electrolyte/sulfur ratios of 5 and 3μL mg^(−1).Even at a high loading of 12.2 mg cm^(−2),the battery affords an areal capacity of 7.5 mA h cm^(−2).